SEASONAL GROWTH OF GMELIN’S LARCH TREE RINGS IN THE ANTHROPOGENICALLY ALTERED CRYOGENIC LARCH FOREST
V. E. Benkova, A. V. Benkova, A. V. Shashkin, D. A. Mashukov, A. S. Prokushkin
Krasnoyarsk Science Centre of the Siberian Branch of Russian Academy of Science, V. N. Sukachev Institute of Forest, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk, Russian Federation
Keywords: northern taiga larch forest, dendrometry, anthropogenic disturbance, weather conditions, logistic growth model, xylogenesis
Abstract
The results of a study of the intraseasonal radial growth of Gmelin larch ( Larix gmelinii (Rupr.) Rupr.) trees growing in a cryogenic larch forest on an anthropogenically modified site (the edge of a seasonal road) and on a natural forest site without anthropogenic disturbances are presented. Continuous measurements of radial growth during the season were conducted on experimental trees using DR-26A point dendrometers during the 2017-2019 seasons, which differed significantly in terms of weather conditions. The dynamics of intra-seasonal growth of the annual ring of an individual tree was characterized by a set of maximum daily values. Using the Pearl-Reed approximating logistic equation ( R 2 = 68-99 %), the main phenological characteristics of tree ring seasonal growth for each tree were determined: the dates of the start and end of the growth season, duration of three stages of the growth season (in days), and the maximum growth intensity (mm/day) during the second stage. It was found that the tree ring width of the annual ring (TRW) is determined by the maximum intensity during the second stage of seasonal growth ( R = 78-97 %). In the anthropogenically modified site, the TRW is significantly wider than in the control area, regardless of the weather conditions during the season. The tree rings formed in the trees on the control site in 2019 was narrower than those in 2018, while they were wider in the anthropogenically modified site. The opposite trends are interpreted based on previously obtained relationships between radial increments and climatic factors (Benkova et al., 2024). The maximum intensity of tree ring growth during the season and TRW in the experimental sites are determined by weather conditions at different stages of xylogenesis. In the anthropogenically altered site, this is the period preceding the growth season (early May), when the weather conditions pre-determine the value of maximum intensity of tree ring growth associated with the stage of formation of new tracheids. In the control site, this is the later period (late May to middle June), when the weather conditions directly affect the process of new tracheid formation.
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